A variety of products such as gowns, sheets, drapes, instruments, etc. which are required during surgery or other aseptic procedures, are used on a daily basis in the normal operation of hospitals, clinics and the like. Where such products are not pre-packaged in a sterile state, it is necessary for the hospital or clinic to sterilize them before use. Furthermore, where these products are not disposable, and are employed more than once, it is necessary that they be cleaned and otherwise prepared for subsequent use. Prior to such use, however, it is essential that such products be sterilized.
Due to the volume of materials involved, it is often necessary to sterilize and store these products for later use. Accordingly, there has been developed a procedure where such products, after cleaning, laundering and the like, are wrapped in sterilization fabric and then sterilized and stored for subsequent use. Disposable sterilization fabric is typically cut into predetermined rectangular shapes and sold as sterilization wraps.
Conventional disposable sterilization wrap is a flat, featureless sheet of material that may occasionally contain one or more additional layers of material for strength or absorbency. Such sterilization wrap is frequently made of inexpensive, relatively impermeable material such as, for example, paper and the like. The properties of these materials have generally influenced folding techniques and wrapping configurations to ensure the sterility of the wrapped tray or article.
For example, U.S. Pat. No. 5,635,134 to Bourne, et al. discloses a multi-ply sterilization wrap which is formed by joining one or more sheets of sterilization wrap (e.g., two separate sheets or one sheet folded over) together to form two similarly sized, superposed panels that allow convenient dual wrapping of an article. As another example, U.S. Patent Application Publication No. 2001/0036519 by Robert T. Bayer discloses a two ply sterilization wrap that is formed of a single sheet of sterilization wrap material which is folded to form two similarly sized, superposed panels that are bonded to each other. As yet another example, U.S. Patent Application Publication No. 2005/0163654 by Stecklein, et al. discloses a sterilization wrap material that has a first main panel and a second panel that is smaller than the main panel. The second panel is superposed and bonded to the central portion of the main panel such that it is contained entirely within the main panel to reinforce the main panel and/or provide additional absorbency.
There are many ways items conventionally wrapped or packaged in sterilization wraps can be contaminated. For example, certain modes of wrap failure such as knife cuts, abrasion and punctures are well-recognized. There are other modes of failure that are as common if not more common. These include pressure cuts, snag cuts and pressure holes.
A pressure cut can appear as a knife cut, but upon closer examination, the fibers around the very edge of the cut have been “welded” or stuck together. The edge of the cut may feel hard to the touch. This type of cut usually follows the perimeter or outline of the bottom of the instrument tray. It may also occur on the top of the instrument tray, if a number of trays have been stacked upon one another. An example of a typical event that may generate a pressure cut would be lifting the front end of a 20 pound tray so that all the weight of the tray is resting on a back edge, and pulling it across the storage shelf before lifting. This is similar to cutting the wrap with scissors; the material is caught between two layers of hard solid interfaces with a shearing action applied to the material.
In a snag cut, the edges of the cut show loose fibers hanging and/or there are individual fibers spanning across the width of the cut. The edges of the cut are not rough or hard, as with the pressure cut. In larger snag cuts, the shape of the cut area resembles a triangle, with the point of the triangle being where the snag began. The snag cut will occur along the edges of the wrapped instrument tray if the tray is very loosely wrapped. Otherwise, this type of cut will occur on the other areas of the tray where the wrap is too loose and can be caught by rough surfaces or corners. This type of cut is generally due to the tray being pulled or dragged across a roughened surface, often an older, well-used sterilizer cart. This cut can also occur when a loosely wrapped area of a tray gets caught on the corners or edges of objects.
A pressure hole may appear to be a tiny opening where the fibers around the very edge of the hole have been “welded” or stuck together. This type of hole is usually found along the perimeter of the bottom of an instrument tray. It may also occur on the top of the instrument tray if a number of trays have been stacked upon it. An example of a typical event that may generate a pressure hole would be a tray being dropped (even a small distance) onto an edge of a cart or storage shelf while being transported to different areas of the hospital.
During typical practice, the sterilization wrap is inspected for holes, tears or other breaches after it is removed from the sterilized article. It has been proposed in International Publication No. WO 2008/083426 A1 “Sterilization Wrapping System” by Spierenburg, that having color differences between superposed layers of a sterilization wrap system could make detection of breaches easier because a viewer looking directly at a breach will notice the contrast between the color of the material around the breach and the material exposed by the breach. However, such a system fails to address the problem of detecting breaches in the sheet of a multi-layer sterilization wrap on the opposite side of the viewer such that the viewer cannot look directly at the breach to see the difference in color.
Accordingly, there is an unmet need for an easy method to inspect a sterilization assembly, package or system that simplifies the task of identifying a breach—particular a breach in a multi-layer sterilization wrap system that is on the opposite side of a viewer.